1) Field of the Invention
The present invention relates to vehicles, and in particular to high clearance vehicles for general agricultural use.
2) Related Art
High clearance agricultural vehicles have been known for years. They are particularly useful in spraying row crops. In this instance, these are typically designed for use with maturing corn of four or five feet in height and in order to avoid damage to the crop, the vehicles have a general clearance at least equal to the height of the rows of crops, (hence the vehicles are relatively tall pieces of equipment). These vehicles generally have at least two drive wheels the width of which allows the vehicle to pass between two different crop rows. The vehicles are also equipped with a boom which extends outwardly from both sides of the vehicle to spray relatively large crop areas at a time.
In one manner of application, sprays are applied to the crops during the tilling stage when the crops are quite small and a conventional ground-type crop sprayer could traverse the field without causing damage to the small plants. However, conventional ground supported crop sprayers are usually not suitable during the latter stages of growth. For example, during the stem extension stage, the likelihood of damage to the standing crops increases if the spray is applied by a ground traversing conventional crop sprayer.
Conventional crop sprayers are even more unsuitable for applying agricultural sprays during the heading and ripening stage of the crop. However, in order to obtain a good yield, it is often necessary to apply spray, for example, a fungicide, during the these stages especially to crops such as, wheat, barley, and the like. Spraying at these latter stages of growth has been typically done by aerial spraying in order to avoid damage to the standing crop. The effectiveness of aerial spraying is dependent in large part upon the weather conditions, and even then, the application of the spray is not as effective as ground spraying if damage to the standing crop can be avoided. Further, the spray must be concentrated when applied by crop aerial dusting because of the limitations of the capacity of the aerial sprayer.
Because spray vehicles operate over rough ground and in tall mature crops, various devices are used to help cushion the vehicle, operator, and boom from the effects of these rough surfaces. Most of these devices suffer from one or more disadvantages such as limited cushioning or bulkiness leading to interference with spraying the crop. A cushioned wheel arrangement, such as the front wheel suspension shown in U.S. Pat. No. 5,066,030, is available for relatively small sprayers with a single steerable wheel. However, such a suspension is not suitable for most larger sprayers or sprayers having two or more steerable wheels. Some available self-propelled sprayers have strut suspensions such as the one disclosed in U.S. Pat. No. 5,597,172. Strut shaft type suspensions may not have the ability to provide all of the traction necessary to move freely about rough terrain. Furthermore, the strut shafts may bend under rough terrain conditions thus making the vehicle less durable.
Sprayer suspensions with strut shafts may also include steel suspension springs immersed in oil. However, these often leak, and require supports with relatively large diameters both above and below the axle which interfere with the crops. Therefore, providing adequate cushioning without adversely affecting the crops continues to be a problem. Further, commercial systems with spring suspension systems have added cab roll on sloping terrain which results from compression of the springs.
U.S. Pat. No. 5,353,988 shows another suspension system. One of the drawbacks of this system is that the swing arms pivot point is high (for ground clearance) and the wheels are low. This configuration can cause problems when the vehicle hits a bump because the wheels move out as much as they do up. Thus, every bump the vehicle hits tends to shove the wheel into the crop which can damage the crop. Moreover, as the vehicle""s load gets heavier or lighter, it changes its wheel track, so that when it""s fully loaded it may be running over the outside rows and when it is empty it may be running over the inside rows.
Because row spacings in row crop situations can vary from field to field, the wheel track of the spray vehicle must be adjusted accordingly. Linkage adjustments may be time-consuming and inconvenient. For example, when spraying solid seeded crops such as wheat or barley, sprayers must drive directly over the plants which may cause damage. An adjustable linkage for a sprayer is shown in U.S. Pat. No. 5,464,243. Other vehicles can manually widen one set of wheels independent from the other to reduce the potentially damaging track of their wheel configurations. However, manually adjusting the wheel configurations can take a considerable amount of time and thus again reduce the vehicle""s productivity.
Steering arrangements for cushioned sprayer wheel assemblies include those with steering arms at the tops of the strut shafts. Such top mounted arm arrangements often have an undesired movement of the steerable wheels over rough ground surfaces, referred to as bump steering, as the steering arms move up and down with the strut shafts.
Conventional vehicle tanks may contain one tank for product, a separate tank for rinse water, and another tank for foam marker fluid. All of these tanks increase the surface area of the vehicle which makes the vehicle more difficult to clean. Further, this multitude of tanks adds unwanted bulk and takes up space on the vehicle which could be put to better use. Connecting these various tanks to each other, to the boom, and to the vehicle involves a complex connection of hoses, circuitry, and clamping devices. These aspects make it difficult for the operator to move around the tanks when it is necessary to plumb them and clean them.
Some booms contain little or no suspension. These booms that do contain suspension may have tilt cylinders out at the ends of the booms to adjust height and provide some suspension or they may have some other elastic member to take the shock out during travel over rough terrain. However, as a boom increases in length, for example, fifty feet or more, the travel at the ends of the boom may become more violent when moving over rough terrain which may cause the boom to hit the ground or, even worse, snap. Moreover, a violently bouncing boom that is uncontrolled may translate this energy to the vehicle making it increasingly less stable and more difficult to control (which, in turn, can effect the precise application of spray to the crops).
Maintaining good visibility from the cab of the spray vehicle to the crops, the boom and nozzles and maintaining a direct line of sight from the cab to the wheels is also important but has been problematic in the past. For example, some commercial systems have the boom and the nozzles mounted behind the cab. This forces the operator to constantly turn and bend to maintain visibility.
Some high clearance vehicles rely on conventional cooling systems to suck air past the engine and the hydraulic oil cooler. These systems may become clogged with dust and debris when the high clearance vehicle is operating in early spring or late fall field environments. When air flow is effected, engine and drive system efficiency is reduced. The possibility of overheating increases also. These problems can lead to decreased fuel efficiency, increased down time, and even worse, permanent damage to the engine and/or the hydraulic oil system.
Most commercial systems contain thrust washers within their steering systems. Thrust washers bear the weight of the load. For example, when the wheels are turned, the wheels pivot and the load bears down on the thrust washers which then carry this thrust force until the vehicle has completed its change in direction. When servicing these thrust washers, some systems require that the operator remove all hoses and connections to the wheels, jack up the vehicle, remove the wheel, and remove the entire hub and kingpin before removal of the thrust washer is possible. This can be a major operation, and it increases vehicle down time, thus decreasing the operator""s and vehicle""s productivity.
Given the above-described deficiencies of existing high clearance vehicles, the industry has a continuing interest in designing such a vehicle with an improved suspension system that minimizes crop interference and bump steer problems, a smoother ride, improved boom visibility and suspension, an improved cooling system, an improved tank design, a wheel configuration which improves traction and minimizes damage to crops, and ready access to operating parts for ease in service and repair.
The above-referenced U.S. patents disclose embodiments that were at least in-part satisfactory for the purposes for which they were intended. The disclosures of all the above-referenced prior United States patent, in their entireties are hereby expressly incorporated by reference into the present application.
It is an object of the present invention to provide an improved suspension for a high clearance vehicle.
It is a further object of the present invention to provide an improved suspension for a high clearance vehicle so crop interference is minimized.
It is another object to provide an improved suspension wherein cushioning and steering components are advantageously located so that crop interference is minimized.
It is yet another object to provide such a suspension which minimizes bump steering problems.
It is a further object to provide a high clearance vehicle having a generally smoother ride over rough ground surfaces than most previously available high clearance sprayers.
It is still another object to provide a row crop sprayer having improved boom visibility and suspension.
It is another object of the present invention to provide an improved cooling system which is also easier to access and maintain.
It is a further object to provide a sprayer having an improved tank design for easier transport and cleaning.
It is an additional object to provide a vehicle having improved traction and a less damaging wheel track.
It is a yet further object of the present invention to provide a vehicle which allows improved access to its operating parts for service and repair.
A high clearance vehicle constructed in accordance with the teachings of the present invention includes a walking beam frame, an independent suspension, a cab, a tank, a boom, and an engine and wheels for propelling the vehicle. A main frame forms part of a walking beam frame which may further include a main truss connected to the main frame, a pair of leg braces connected to the main truss, an elastic member connected to each leg brace, a swing arm connected to each elastic member, and a rear telescoping axle beam connected to the main frame. A pair of rear legs are connected to the rear telescoping axle beam and a pair of front legs are connected to each swing arm. Each leg includes a top and a bottom, an integral kingpin, and a hub mount. The wheels are connected to each hub mount. A steering arm is connected to the top of the leg.
The walking beam frame provides shock absorption by allowing the frame to oscillate or flex front to back and side to side about pivot points to ensure generally constant ground contact with all four wheels. It does this by having each front leg connected to a rear leg so that the pair rotates about a pivot point in a coordinated oscillation. The rear axle beam also rotates about a pivot point. In addition to the walking beam frame, independent suspension is provided through the use of elastic members. For example, an elastic member may be operably connected between the swing arms and the leg braces to provide independent suspension to the front legs. Additionally, independent suspension may be provided to the legs individually by use of an elastic member within the confines of a wheel rim attached to each of the legs. This elastic member may be part of a knee action suspension. The knee action suspension may be on any or all of the wheels. Moreover, because the inventive oscillating, walking beam frame in combination with independent suspension operates without a tie rod, there is a reduction in the amount of bump steering.
The walking beam frame may include a crab steering device which acts in cooperation with the frame. The crab steering device includes an actuating member mounted to at least one of the rear legs and a telescoping round tubular axle beam connected to the rear legs. The round tubular rear axle allows for rotation of two round tubular members which make up the axle. The actuating member is mounted to the main frame and to at least one of the round tubular rear frame members to allow the rear wheels to xe2x80x9ccrabxe2x80x9d or xe2x80x9cdog legxe2x80x9d. The actuating member may be mounted so that the vehicle can track left, track right, or track both left or right.
The high clearance vehicle of the present invention also has a hinged stacked assembly including a condenser, an oil cooler, and a radiator mounted behind the engine of the vehicle. A hinged door covers the stacked assembly. The door has a hole in it covered by a cylindrical screen which is operably associated with the door and covered with a plastic cover. Within the cylindrical screen is a fan blade for drawing air through the screen. An axle is connected to the fan blades and internal baffles communicate with a portion of the axle. A radiator fan draws air through the screen past the fan blades creating a vacuum for airborne debris. The debris sucked on to the cylindrical screen drops off as the cylindrical screen rotates past the baffles. Thus, a flow of fresh air to the condenser, oil cooler, and radiator remains constant.
The kingpin is integral with at least one of the front legs. The kingpin inserts into a hole in the swing arm or A-shaped frame. Each leg includes a top and a bottom. The steering arm is connected to the top of the leg to provide control to the leg when steering the vehicle. The positioning of the steering arm allows for maximum clearance underneath the beam frame as well.
Below the swing arm is a lower bushing which is adjacent to a segmented thrust washer. In one embodiment, the segmented thrust washer is made of high molecular weight plastic and divided into a multitude of pieces to allow for easy maintenance. Each segment may have either a lobed end or a receiving end. Each lobed end fits into a receiving end on another segment. During maintenance, the A-shaped frame can be raised off of the thrust washer and the lower bushing so that the thrust washer is accessible.
The tank is comprised of a large main tank with a bulkhead inserted inside the main tank to split the tank into at least two (2) compartments. The larger compartment is for the product and the smaller compartment is for fresh water to rinse the tank after the application of the product is complete. There is a hole in the top of the main tank to allow a cylindrical tank to be dropped within, forming a third compartment that is designed to be pressurized to contain a foam marker fluid.
Connected to the frame is also a boom lower lift arm and an upper lift arm. The lower lift arm and the upper lift arm carry the boom which is rotatably connected to at least one lift arm. The configuration of the boom maximizes operator visibility. An elastic member is connected to the lower lift arm for supporting the weight of the boom by forming a falling rate suspension.
These, and other, aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.